Research ArticleDirectional Blasting Technology of Slit Charge for GeologicalDisposal of High-Level Radioactive Waste

Ke Man 12 Xiaoli Liu 3 Ju Wang12 and Xiyong Wang12

1Division of Environment Engineering Beijing Research Institute of Uranium Geology Beijing 100029 China2Key Laboratory of China National Nuclear Corporation on High Level Radioactive Waste Geological DisposalBeijing 100029 China3State Key Laboratory of Hydroscience and Hydraulic Engineering Tsinghua University Beijing 100084 China

Correspondence should be addressed to Ke Man man_kesinacn

Received 1 August 2018 Accepted 10 September 2018 Published 3 October 2018

Guest Editor Zhanguo Ma

Copyright copy 2018 KeMan et al(is is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Based on the slit charge technology the blasting progress and the blasting theory have been studied in detail Combined with thehigh-level radioactive waste geological disposal in which the excavation damaged zone of the surrounding rock is required assmall as possible the testing of the Beishan exploration tunnel (BET) has been studied and the blasting parameters have beendesigned using the slit charge technology (eoretically the rock failure criterion has been proposed which adopted the dynamicmechanical parameters such as the dynamic compress strength dynamic tensile strength dynamic modulus dynamic passionratio dynamic fracture toughness and dynamic stress intensity factor Furthermore the blasting test has been carried out underthe same tunnel face with left and right sides simultaneously and it can be found that the blasting effect with the slit chargetechnology is better than another side which verified the useful and scientific meaning of this technology It should be noticed thatthe blasting method includes numerous blasting parameters which interact with each other (ose blasting parameters obtainedjust limited the slit charge and the result and the theoretical knowledge could be applied to the blasting and excavation of the deepgeoengineering and HLW geodisposal

1 Introduction

High-level radioactive waste is an inevitable product of thenuclear industry However high-level radioactive waste hasbeen accumulated by the fast development of nuclear powerconstruction in China According to National Nuclear PowerDevelopment and Long-term Plan (2005ndash2020) [1] approvedby the State Council it is expected that by 2020 the installedcapacity of nuclear power will reach 70 million kilowatts thecapacity of the installation is 30 million kilowatts and therewill be 13 8200 tHM spent fuel produced by the whole lifeperiod of nuclear power that should be safely disposed whichbecomes a major safety problem to be solved

According to the strategy for the geological disposal ofhigh-level radioactive waste the construction of URL(Underground Research Laboratory) for the high-level ra-dioactive waste is required during the 13th Five-Year Plan in

China and the URL is a necessary verification facility for theconstruction of high-level radioactive waste geological dis-posal As one of the largest projects nuclear waste disposalhas been raised to the national level (erefore the con-struction of the URL for high-level radioactive waste isimminent and the demand is very urgent

At present the deep geological disposal is the universalacceptable solution to the disposal of high-level radioactivewaste [2ndash5] that is to bury the high radioactive waste ina geological body with a depth of about 500ndash1000m from thesurface So that it is permanently isolated from the humanliving environment (erefore the deep geological disposalmethod will be adopted in China [6ndash8] How to excavate theURL and the disposal repository and how to design the rockblasting implementation plan during the constructionprocess are of vital significance to ensure the stability andsafety of the repository

HindawiAdvances in Civil EngineeringVolume 2018 Article ID 6401545 9 pageshttpsdoiorg10115520186401545

Drilling and blasting method or TBM mechanical ex-cavation method is usually used for the chambers excavationof high-level radioactive waste disposal No matter whichexcavation method is adopted the rock breaking effect andthe disturbance to the surrounding rock are two mainconsiderable factors in the construction and monitoringprogress and these two factors restrict each other [7 8] Notonly the over excavation of the surrounding rock is requiredbut also the under excavation is demanded during theconstruction that is the positive energy should be pro-moted and the negative energy should be limited whichcorrespond to a high excavation speed and a small rockdamaged zone separately

How to control the excavation concisely and induce therock crack occurring growing penetrating and generatinga prefractured surface is a main question and key problemfor the stability of rock engineering [9ndash15] such as theunderground engineering mine mining tunnel construc-tion and railway application

In 1950s the smooth blasting method has been putforward in Sweden Because the damage of surrounding rockcan be effectively controlled by this method and it also canefficiently break rock the smooth blasting technology hasbeen popularized in a large amount and has been applied tothe engineering Especially the design and selection ofblasting parameters are very important (ere are manyscholars at home and abroad who have carried out a largenumber of analysis and research [16ndash22] based on differentstarting points of the blasting mechanism

Among them the blasting mechanism of the directionalfracture technology using the slit charge is analyzed [23ndash28]and the differences and advantages between the directionalfracture blasting of the slit charge and the cutting hole and theconcentrated blasting are compared in detail Furthermorethe blasting formula of the slit charge can be used to realizethe directional fracture of the tunnel better Meanwhile coalmine and other engineering have been carried out and a goodblasting effect has been achieved(is paper tries to use the slitcharge technology combined with the geological disposal ofhigh-level radioactive waste to carry out the directionalblasting test of the slit charge and to compare and analyze theblasting effect finally to give a guidance to the excavation ofthe subsequent disposal engineering

2 Engineering Background of BET

As a technical research facility for the geological disposal ofhigh-level radioactive waste in China the BET (Beishan ex-ploration tunnel) facility has carried out various constructionskills related to the excavation engineering such as the blastingtest rock deformationmonitoring EDZmonitoring advanceddetection and grouting test (e main difference between BETproject and the other underground projects is that it demandsthe EDZ value as small as possible As the underground re-pository facilities need to be safe for thousands of years itmeans that the nuclides must be ensured that they could notmigrate from the surrounding rock to the nature

In view of the actual working conditions of the BET fa-cility the blasting parameters of the slit charge used in the

drilling and blasting test are designed and the directionalblasting test of the slit charge is emphasized (e cutting andslit charge blasting technology of the granite rock in this areais analyzed and discussed

BET facility is located in Gobi Gansu Province about80 km northeast of Yumen City (e main project of BETfacilities includes the tunnel door inclined shaft alley waterstorehouse test chamber shelter ventilation hole and thewater supply power supply and ventilation system (esurrounding rock of the project is mainly granite and its staticcompressive strength is 150MPa while the tensile strength is13MPa (e fracture (F18) moved toward 60deg which tendedto be NW or SE with a dip angle of 75sim85deg (e tectonicfracture zone is fragmented and fractured especially in thecenter of the tectonic belt (e blasting parameters arequantified by theoretical calculation and semiempiricalanalysis respectively (e longitudinal wave velocity of therock is 3500ms (e emulsion explosive is used in thesurrounding blasting holes to be cut into several segments onaverage using air spacing with uncoupled charge

(e blasting excavation test and the other tests arecarried out as shown in Figure 1

It is located in themonitoring chamber at the bottom siteof the inclined shaft which is close to the test chamber fordrilling and blasting and each blasting cycle footage is 2m

Amillisecond delay with a nonelectric detonator is used todetonate the cutting holes adopt continuous coupling chargethe auxiliary holes and the bottom holes adopt continuousnoncoupling charge and the surrounding holes adopt the airinterval with noncoupling charge to bind the interval of theexplosive to the detonator and then attach the bamboo sheetto the bottom of the hole (e blockage length of the blastinghole is as follows the surrounding hole auxiliary hole is notless than 20 cm and the cutting hole is not less than 40 cm

At the same time in order to ensure the blasting effectduring construction the quality of the drilling holes need tobe controlled so as to achieve a standard of parallelismstraightness neatness and accuracy

Firstly parallel means that the drilling holes are parallel toeach other and parallel to the roadway heading directionSecondly straight means that the blasting hole must be per-pendicular to the blasting face (irdly neat means that thedrilling holes are on the same bottom which can guarantee thefracture of the tunnel at the same position Fourthly accuratemeans that the holes are drilled concisely the hole arrangementis accurate and the contour line cannot be deviated much

(e location of the drilling holes should be on thepredesigned contour line of the roadway (e bottom of thehole should be controlled within 100mm of the contour lineand the inclination angle should be controlled within 3deg

During the drilling implementation process we can mea-sure and record the hole parameters by means of the anglegauge steel ruler and straight stick to ensure the drilling quality

3 Rock Failure Mechanism of DirectionalBlasting Using Slit Charge

(e directional blasting technology of slit charge is mainlybased on the principle of shaped charge blasting (e slit

2 Advances in Civil Engineering

pipe can be made of different materials such as the PVC tubeor copper tube and its wave impedance is different from thatof rock (e size of the slit pipe is determined by the di-ameter and length of ordinary rock emulsion explosive andthe inside and outside diameters of the slit pipe At the sametime the slit pipe with different cutting widths and differentcutting angles can be machined

As shown in Figure 2 the left side is the slit pipe and itslongitudinal section is along the diameter direction and theright side is the detailed description of the slit pipersquos crosssection where A is the longitudinal side view of the slit pipewith a certain width of the cutting seam and B is the crosssection of the slit pipe while 1 is the loading part 2 is the airmedium 3 is the slit pipe 4 is the hole wall and 5 is the rockparticle with a distance R away from the center of the ex-plosive bag (e distance R can also be described by the axisangle θ and the distance from the hole wall r r1 is the radiusof the explosive r2 is the radius of the slit pipe and b is thegap between slit pipe and borehole wall Obviously thereexists a relationship between those parameters that isR r + r2 + b

When the explosive is detonated the explosion shockwave is generated instantaneously (e shock wave acts onthe surface of the slit pipe Between them some of the shockwaves acting on the cutting seam will continue to propagatealong the slit and some of the shock waves acting on the slitpipersquos surface will produce the transmission and reflectionwaves in which the impact of the transmissive wave enteringthe gap will be acted on the hole wall And the reflectedtension wave coupled with the shock wave inside the slitpipe which is also mixed with exploding gas has a certainperiod resulting in the energy cumulative effect

(e impact wave at the cutting seam propagatesdirectionally along the slit due to the energy cumulativeeffect until it acts on the rock wall (en the rock istransmitted and broken (e subsequent exploding gascontinues to expand and extend along the blasting induced

crack until the rupture in the blasting area (erefore theenergy cumulative effect and directional blasting of theexplosive could be realized by the slit charge technology andit also has a certain protective effect on the wall surface of thenoncutting direction Above all it is of great significance tothe rational use of explosives and the damage control of rockengineering

From the point of the blastingmechanism because of theexistence of the slit seam the stress condition between theslit seam holes is not the common effect of compression bythe shock wave and the exploding gas but the tensile stressforced on the rock which changes the rock failure mech-anism Rock as a quasibrittle material it is known that itscompressive strength is far greater than its tensile strengthand the difference is at least one order of magnitude Usuallyits compressive strength is several hundred MPa but itstensile strength is generally several MPa According to thosefactors if we want to crush the rock efficiently it needs to bestretched in the tensile stress state as more as possible

No matter which testing methods are used such asuniaxial compression three axial compression and direct orindirect tensile tests from the mesoangle the failure

Figure 1 Site for the blasting test

5

r1r

R

1

23

4

r2bB

A

θ

Figure 2 Schematic of the slot blasting principle

Advances in Civil Engineering 3

mechanism is analyzed either to be tensile failure or to betensile-shear failure Mainly it is a pure compressive stresscarried out on the rock by the shock wave and the stress waveunder blasting Only when the wave propagates to the freesurface the wave reflection occurs and the tensile unloadingwave is produced (erefore the rock is subjected to tensilestress which is beneficial to the rock cracking But thecompression failure is produced on the rock wall very nearthe charge hole and the rock wall is directly damaged intorock powder by the explosion wave

Precisely because of the existence of the slit chargeblasting hole the compression and tensile shock waves alongthe slit direction are more strongly influenced than that inthe other directions Especially the crack surface which hasbeen caused by the early shock wave has been largely im-pacted by the subsequent shock wave causing the rock massin the slit direction to be more easily unloaded spalling andcrushing At the same time explosive gas is more likely toexpand along these cracks and the role of explosive gas inthe slit is more intense than that originated by ordinarycartridge Definitely because of the slit charge the rock masssurrounding the cutting seam is much easier to producetensile fracture and easier to be broken out

Furthermore the role of slit charge for the single blastinghole can be divided into the following aspects Firstly thecutting seam plays a good role in accumulating the explosivewave after blasting Most of the explosive energy is prop-agated along the cutting seam to the rock wall of the blastinghole and the tangential stress produced by the blastingcauses the radial crack around the blasting hole and thecrack is extended forward by the subsequent explosive gasSecondly the slit pipe has a negligible effect on the explosiveenergy Because of the slit pipe explosive energy and det-onating gas are limited to the slit pipe for a certain periodwhich is a little longer than that of the nonslit pipe

(erefore the energy will be released for a longer timeand the residence time of the explosive gas in the charge spaceis prolonged Moreover the slit pipe has a good guiding effecton blasting energyMost of the energy is released along the slitdirection which is more fully blasted and the deformation ismuch more than the direction vertical to the slit or otherdirections Finally the slit charge technology has a certainprotective effect on the blasting hole wall Due to the waveresistance difference between the slit pipe and the rockmedium in addition to the transmission wave of the slit pipethe reflection wave will also occur which could be limited inthe slit pipe and wait for the energy to be released again Andthe released energy is still more transmitted from the slitDuring this process the rock blasting hole which is not alongthe slit direction is protected

As for the blasting engineering the cutting seam packageand the slit charge technology are used in the surroundingblasting hole which can fully play the protective effect on therock wall and also lead to the directional and concentratedeffects

It should be noted that due to the existence of the slithole a free surface is produced in the rock mass and thestress concentration occurs It means that the stress here isfar greater than the stress in other places and the rock

between the slit holes is subjected to not only the impactpressure but also the tensile stress Especially the connecteddirection of the slit hole is the place where the maximumtensile stress is generated and the rock failure caused bytensile stress is more likely to occur In the case of simul-taneous initiation of a double slit charge way the stress waveis firstly propagated along the slit direction resulting in theinitial crack (en with the opposite propagation of thestress waves between the two holes the peak stress of theblasting can reach a number of several GPa in the center Sothe initial crack can propagate through each other undersuch high stress

At the same time from the point of the superposition ofthe stress wave the crack formation should be analyzed It isfound that the penetrating crack can be formed between thetwo holes through the reasonable design of the blasting holediameter the slit pipe diameter the slit charge size and so on

To sum up the slit hole can lead to the rock failure moreeasily along the line between the slit holes and the slit chargeplays a good guidance role in the failure process which ismore conducive to the performance of the explosive

4 Directional Blasting Technology UsingSlit Charge

Definitely the characteristics of the high-level radioactivewaste geological disposal demand a higher safety grade forthe buried nuclear waste Rock permeability increases by theformation of new cracks in the damaged area and the ex-pansion of the original fissure in the rock (erefore thepotential channel for the nuclide migration is provided Inaddition the mechanical properties of the rock and theoperation period of the disposal repository are highlyinfluenced by the excavation damage No matter whichexcavation method is adopted the rock breaking effect andthe disturbance to the surrounding rock are two mainconsiderable factors in the construction and monitoringprogress and these two factors restrict each other

For the geological disposal of high-level radioactivewaste it is very important to recognize the relationshipbetween the elastic modulus deformation permeabilitycoefficient heat conduction coefficient and solute diffusioncoefficient of the excavation zone

At the same time the blasting design and damageverification for rock mass are still a hot topic in blastingengineering Especially for the geological disposal of high-level radioactive waste how to carry out the blasting designof engineering rock mass is a challenge

(e geological disposal facilities of high-level radioactivewaste extend from the surface to a certain depth in the deepunderground which requires that the surrounding rockdamage caused by the excavation is as small as possiblebecause the fracture of the surrounding rock will continue toinitiate expand or even interconnect in the rock massresulting in the loss of the disposed nuclear waste in a certainperiod of time which is absolutely not allowed No matterblasting or mechanical excavation method is used thesurrounding rock will be damaged and this damage isunavoidable

4 Advances in Civil Engineering

(erefore it is very important to adopt a suitable methodto reduce the rock damage(rough the above description itcan be seen that accurate blasting could be achieved by theslit charge directional blasting technology which can playthe role of directional blasting energy gathering blastingand the protection of surrounding rock And it can lead toa small damage range and can ensure the long-term safety ofthe geological disposal of high-level radioactive waste

(e essence of directional fracture blasting of the slitcharge is that the cutting slit with different angles shapesand numbers on the certain density and strength explosiveshell is formed (en the charge mode with a certain ac-cumulation of explosive energy is generated between the slitcharge and the blasting hole (e design blasting parametersand the failure criteria of directional blasting using the slitcharge are discussed below

41 Design of the Blasting Parameters (e hole spacing isquantified by the theoretical calculation and semiempiricalanalysis (e strength coefficient of the rock in the experi-mental tunnel is 8 and the wave velocity is 3500ms (eemulsion explosive is used and the air uncoupled chargeway is adopted Explosive density is 1000 kgm3 and thevelocity of the explosive is 4000ms (e diameter of theexplosive is 32times10minus2m the diameter of the blasting hole is42times10minus2m and the length of the hole is 20m

According to the blasting principle the radial stress andtangential stress of rock mass at a distance r away from thecenter of the borehole are respectively

σr P2Tb

T1113874 1113875

a

σθ bσr

(1)

where σr is the radial stress σθ is the shear stress b is theratio of the tangential stress to the radial stress andb μ(1minus μ) a is the attenuation index of the stress waveand a 2minus b Tb is the radius of the blasting hole T is theradius of the explosive and P2 is the impact stress on theblasting hole wall surface

(e impact pressure on the hole wall as using theuncoupling charge is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6

n (2)

where ρ0 is the explosives densityD is the explosive velocitywhile dc and db are the diameter of the explosive and theblasting hole and n is the pressure increasing coefficient ofthe detonation impacting on the hole wall

However when the air uncoupled charge is adopted theimpact pressure on the hole wall is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6Lc

Lc + La1113888 1113889n (3)

where La is the length of the air column interval and Lc is thelength of the explosive charged

42 Criterion of the Directional Blasting TechnologyUnder the action of tangential tensile stress the criterioncondition of breaking fracture is

σθ ge Std (4)

where Std is the dynamic tensile strength of the rockMoreover the relationship between tangential stress andradial stress is

σθ μσr

(1minus μ) (5)

Std C + σθ tanφ (6)

where C is the dynamic cohesion and φ is the dynamicfriction angle of rock

According to Formulas (4)ndash(6) under the condition ofthe single hole when the crack is formed by the tangentialtensile stress the radial stress σr should be satisfied

σr ge(1minus μ)Std

μ (7)

At the same time at the crack tip under the blastingstress wave action it is

KdI

πr

radicP2Ylowastmin (8)

where KdI is the dynamic fracture toughness and Ylowastmin is

a dimensionless stress intensity factor at the crack tip whichreflects the size and shape of the crack and it is an inherentindex of the rock material

Under the continuous action of the explosive stress wavethe crack continues to expand and should be satisfied asfollows at the crack tip

KId gtKdI (9)

where KId is the dynamic stress intensity factor at the cracktip which varies with the crack propagation

It can be seen that Formula (7) is the criterion conditionof initial crack formation during slit charge blasting andFormula (9) is the criterion condition of crack propagationand extension under the blasting progress

5 Directional Blasting Experiment UsingSlit Charge

According to the actual engineering geology the blasting testusing the slit charge technology was carried out at the samefree face with the left and right positions separately Amongthem the surrounding hole of the left side uses the ordinarycharge structure and the surrounding hole of the right sideadopts a slit charge structure (erefore it can make a moreaccurate comparison and analysis for the slit charge tech-nique (e blasting effect can be measured by parameterssuch as the over excavation amount and the half hole ratioafter blasting (e specific test is described as follows

51 Production of the Slit Pipe (e slit pipe is made of thePVC tube with an outer diameter of 32mm and an inner

Advances in Civil Engineering 5

diameter of 30mm With an emulsion explosive inside thediameter of the explosive is 32mm and the slit width of theslit pipe is 2mm as shown in Figure 3

It must be noticed that in the process of charging thedirection of the slit must be consistent with the direction ofthe contour of the tunnel cross section Otherwise theexplosive energy will burst more along the other directionsbut induce the tunnel forming worse

It is a key point that must be paid attention before thepreparation of the slit charge and it is also the inherentattribute determined by the directional fracture blastingprinciple of the slit charge

52 Arrangement of the Blasting Hole (e distances of thesurrounding hole both in the left side and the right side were300mm As for the left side the ordinary explosive chargewas installed with three intervals and each length was550mm At the bottom of the hole it was charged with 05volume explosive and the other 025 volumes were installedat each section However the surrounding hole in the rightside was charged using the slit charge with the same installedway and explosive quantity

(e blasting cutting method is straight parallel cuttingway (e layout of the blasting hole before and after drillingis shown in Figure 4

53 Blasting Scheme Based on the above theory of di-rectional fracture technology of slit charge the blasting

scheme is designed(e blasting scheme for the slit charge isshown in Figure 5

(e blasting sequence is divided into 9 segments whichstarts from the cutting hole auxiliary hole to the sur-rounding hole and in the end to the bottom hole

(e length of blockage in the cutting hole is 600mm andthat in the other holes is 300mm

(e number of explosives and detonator segments ineach hole is shown in Table 1 and the section area is1215m2 and the specific charge is 251 kgm3

54 Blasting Effect (e designed footage driving cycle is 2meters while the penetration of blasting has reached 17min the left and 195m in the right which corresponds to theordinary and slit charge separately Meanwhile the utili-zation ratio of blasting hole in the right is higher

(e right side using the slit charge has more than 90 ofthe half hole rate and the blasting effect is smooth and evenHowever the effect of the smooth blasting in the left side isnot so good As can be seen from Figure 6 the rock concaveand convex exist a lot and the half-hole ratio is low

Image process of the profile after blasting and the ratio ofover excavation or under excavation are calculated by theproportional image It is found that over excavation quantityof the right side using the slit charge is small than that in theleft side And it shows a better blasting effect using the slitcharge (ose phenomenon and descriptions illuminate thatthe surrounding holes using the slit charge could make thecross section contour of the tunnel better and smooth afterblasting

Figure 3 Slit pipe

(a) (b)

Figure 4 Borehole distribution

6 Advances in Civil Engineering

Furthermore the variety between the charge composi-tion and the charge structure is the main reason for thedifference of the blasting effect

According to the blasting principle described above itcan be found that as the surrounding hole adopts the slitcharge way it can be easier to achieve directional fracture

123

456

7

89

10

11 1213

14

15

1617

18

19

20

2122

23

24

25

2627

28

29

30

31

3233

34

35

36

37

3839 40

41

42

43

44

45

4647

48

49

50

51

5253

5455

5657 58 59 60 61 62

6364

65

66

67

68

69

70

71

72

8073 74 75 76 77 78 79

298

485 517485

442

435

529

4542150439

442

6154300

1054

200

2000

88deg

35560

425 594 629 173

Figure 5 Blasting scheme of the slit charge technology

Table 1 Blasting parameters table for the scheme

Hole name Hole number Number of holesCharge quantity

Detonator orderEach hole Total weight (kg)

Empty hole 1 1 0 00Cutting hole 2ndash7 6 5 90 1Auxiliary hole 8ndash10 3 5 45 3Auxiliary hole 11ndash12 2 5 30 5Auxiliary hole 13ndash21 9 35 945 7Auxiliary hole 22ndash32 11 25 825 9Auxiliary hole 33ndash46 14 25 105 11Peripheral hole 47ndash72 26 15 90 15Bottom hole 74ndash79 6 3 54 17Bottom hole 7380 2 3 18 19Total 80 609

Advances in Civil Engineering 7

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

pipe can be made of different materials such as the PVC tubeor copper tube and its wave impedance is different from thatof rock (e size of the slit pipe is determined by the di-ameter and length of ordinary rock emulsion explosive andthe inside and outside diameters of the slit pipe At the sametime the slit pipe with different cutting widths and differentcutting angles can be machined

As shown in Figure 2 the left side is the slit pipe and itslongitudinal section is along the diameter direction and theright side is the detailed description of the slit pipersquos crosssection where A is the longitudinal side view of the slit pipewith a certain width of the cutting seam and B is the crosssection of the slit pipe while 1 is the loading part 2 is the airmedium 3 is the slit pipe 4 is the hole wall and 5 is the rockparticle with a distance R away from the center of the ex-plosive bag (e distance R can also be described by the axisangle θ and the distance from the hole wall r r1 is the radiusof the explosive r2 is the radius of the slit pipe and b is thegap between slit pipe and borehole wall Obviously thereexists a relationship between those parameters that isR r + r2 + b

When the explosive is detonated the explosion shockwave is generated instantaneously (e shock wave acts onthe surface of the slit pipe Between them some of the shockwaves acting on the cutting seam will continue to propagatealong the slit and some of the shock waves acting on the slitpipersquos surface will produce the transmission and reflectionwaves in which the impact of the transmissive wave enteringthe gap will be acted on the hole wall And the reflectedtension wave coupled with the shock wave inside the slitpipe which is also mixed with exploding gas has a certainperiod resulting in the energy cumulative effect

(e impact wave at the cutting seam propagatesdirectionally along the slit due to the energy cumulativeeffect until it acts on the rock wall (en the rock istransmitted and broken (e subsequent exploding gascontinues to expand and extend along the blasting induced

crack until the rupture in the blasting area (erefore theenergy cumulative effect and directional blasting of theexplosive could be realized by the slit charge technology andit also has a certain protective effect on the wall surface of thenoncutting direction Above all it is of great significance tothe rational use of explosives and the damage control of rockengineering

From the point of the blastingmechanism because of theexistence of the slit seam the stress condition between theslit seam holes is not the common effect of compression bythe shock wave and the exploding gas but the tensile stressforced on the rock which changes the rock failure mech-anism Rock as a quasibrittle material it is known that itscompressive strength is far greater than its tensile strengthand the difference is at least one order of magnitude Usuallyits compressive strength is several hundred MPa but itstensile strength is generally several MPa According to thosefactors if we want to crush the rock efficiently it needs to bestretched in the tensile stress state as more as possible

No matter which testing methods are used such asuniaxial compression three axial compression and direct orindirect tensile tests from the mesoangle the failure

Figure 1 Site for the blasting test

5

r1r

R

1

23

4

r2bB

A

θ

Figure 2 Schematic of the slot blasting principle

Advances in Civil Engineering 3

mechanism is analyzed either to be tensile failure or to betensile-shear failure Mainly it is a pure compressive stresscarried out on the rock by the shock wave and the stress waveunder blasting Only when the wave propagates to the freesurface the wave reflection occurs and the tensile unloadingwave is produced (erefore the rock is subjected to tensilestress which is beneficial to the rock cracking But thecompression failure is produced on the rock wall very nearthe charge hole and the rock wall is directly damaged intorock powder by the explosion wave

Precisely because of the existence of the slit chargeblasting hole the compression and tensile shock waves alongthe slit direction are more strongly influenced than that inthe other directions Especially the crack surface which hasbeen caused by the early shock wave has been largely im-pacted by the subsequent shock wave causing the rock massin the slit direction to be more easily unloaded spalling andcrushing At the same time explosive gas is more likely toexpand along these cracks and the role of explosive gas inthe slit is more intense than that originated by ordinarycartridge Definitely because of the slit charge the rock masssurrounding the cutting seam is much easier to producetensile fracture and easier to be broken out

Furthermore the role of slit charge for the single blastinghole can be divided into the following aspects Firstly thecutting seam plays a good role in accumulating the explosivewave after blasting Most of the explosive energy is prop-agated along the cutting seam to the rock wall of the blastinghole and the tangential stress produced by the blastingcauses the radial crack around the blasting hole and thecrack is extended forward by the subsequent explosive gasSecondly the slit pipe has a negligible effect on the explosiveenergy Because of the slit pipe explosive energy and det-onating gas are limited to the slit pipe for a certain periodwhich is a little longer than that of the nonslit pipe

(erefore the energy will be released for a longer timeand the residence time of the explosive gas in the charge spaceis prolonged Moreover the slit pipe has a good guiding effecton blasting energyMost of the energy is released along the slitdirection which is more fully blasted and the deformation ismuch more than the direction vertical to the slit or otherdirections Finally the slit charge technology has a certainprotective effect on the blasting hole wall Due to the waveresistance difference between the slit pipe and the rockmedium in addition to the transmission wave of the slit pipethe reflection wave will also occur which could be limited inthe slit pipe and wait for the energy to be released again Andthe released energy is still more transmitted from the slitDuring this process the rock blasting hole which is not alongthe slit direction is protected

As for the blasting engineering the cutting seam packageand the slit charge technology are used in the surroundingblasting hole which can fully play the protective effect on therock wall and also lead to the directional and concentratedeffects

It should be noted that due to the existence of the slithole a free surface is produced in the rock mass and thestress concentration occurs It means that the stress here isfar greater than the stress in other places and the rock

between the slit holes is subjected to not only the impactpressure but also the tensile stress Especially the connecteddirection of the slit hole is the place where the maximumtensile stress is generated and the rock failure caused bytensile stress is more likely to occur In the case of simul-taneous initiation of a double slit charge way the stress waveis firstly propagated along the slit direction resulting in theinitial crack (en with the opposite propagation of thestress waves between the two holes the peak stress of theblasting can reach a number of several GPa in the center Sothe initial crack can propagate through each other undersuch high stress

At the same time from the point of the superposition ofthe stress wave the crack formation should be analyzed It isfound that the penetrating crack can be formed between thetwo holes through the reasonable design of the blasting holediameter the slit pipe diameter the slit charge size and so on

To sum up the slit hole can lead to the rock failure moreeasily along the line between the slit holes and the slit chargeplays a good guidance role in the failure process which ismore conducive to the performance of the explosive

4 Directional Blasting Technology UsingSlit Charge

Definitely the characteristics of the high-level radioactivewaste geological disposal demand a higher safety grade forthe buried nuclear waste Rock permeability increases by theformation of new cracks in the damaged area and the ex-pansion of the original fissure in the rock (erefore thepotential channel for the nuclide migration is provided Inaddition the mechanical properties of the rock and theoperation period of the disposal repository are highlyinfluenced by the excavation damage No matter whichexcavation method is adopted the rock breaking effect andthe disturbance to the surrounding rock are two mainconsiderable factors in the construction and monitoringprogress and these two factors restrict each other

For the geological disposal of high-level radioactivewaste it is very important to recognize the relationshipbetween the elastic modulus deformation permeabilitycoefficient heat conduction coefficient and solute diffusioncoefficient of the excavation zone

At the same time the blasting design and damageverification for rock mass are still a hot topic in blastingengineering Especially for the geological disposal of high-level radioactive waste how to carry out the blasting designof engineering rock mass is a challenge

(e geological disposal facilities of high-level radioactivewaste extend from the surface to a certain depth in the deepunderground which requires that the surrounding rockdamage caused by the excavation is as small as possiblebecause the fracture of the surrounding rock will continue toinitiate expand or even interconnect in the rock massresulting in the loss of the disposed nuclear waste in a certainperiod of time which is absolutely not allowed No matterblasting or mechanical excavation method is used thesurrounding rock will be damaged and this damage isunavoidable

4 Advances in Civil Engineering

(erefore it is very important to adopt a suitable methodto reduce the rock damage(rough the above description itcan be seen that accurate blasting could be achieved by theslit charge directional blasting technology which can playthe role of directional blasting energy gathering blastingand the protection of surrounding rock And it can lead toa small damage range and can ensure the long-term safety ofthe geological disposal of high-level radioactive waste

(e essence of directional fracture blasting of the slitcharge is that the cutting slit with different angles shapesand numbers on the certain density and strength explosiveshell is formed (en the charge mode with a certain ac-cumulation of explosive energy is generated between the slitcharge and the blasting hole (e design blasting parametersand the failure criteria of directional blasting using the slitcharge are discussed below

41 Design of the Blasting Parameters (e hole spacing isquantified by the theoretical calculation and semiempiricalanalysis (e strength coefficient of the rock in the experi-mental tunnel is 8 and the wave velocity is 3500ms (eemulsion explosive is used and the air uncoupled chargeway is adopted Explosive density is 1000 kgm3 and thevelocity of the explosive is 4000ms (e diameter of theexplosive is 32times10minus2m the diameter of the blasting hole is42times10minus2m and the length of the hole is 20m

According to the blasting principle the radial stress andtangential stress of rock mass at a distance r away from thecenter of the borehole are respectively

σr P2Tb

T1113874 1113875

a

σθ bσr

(1)

where σr is the radial stress σθ is the shear stress b is theratio of the tangential stress to the radial stress andb μ(1minus μ) a is the attenuation index of the stress waveand a 2minus b Tb is the radius of the blasting hole T is theradius of the explosive and P2 is the impact stress on theblasting hole wall surface

(e impact pressure on the hole wall as using theuncoupling charge is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6

n (2)

where ρ0 is the explosives densityD is the explosive velocitywhile dc and db are the diameter of the explosive and theblasting hole and n is the pressure increasing coefficient ofthe detonation impacting on the hole wall

However when the air uncoupled charge is adopted theimpact pressure on the hole wall is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6Lc

Lc + La1113888 1113889n (3)

where La is the length of the air column interval and Lc is thelength of the explosive charged

42 Criterion of the Directional Blasting TechnologyUnder the action of tangential tensile stress the criterioncondition of breaking fracture is

σθ ge Std (4)

where Std is the dynamic tensile strength of the rockMoreover the relationship between tangential stress andradial stress is

σθ μσr

(1minus μ) (5)

Std C + σθ tanφ (6)

where C is the dynamic cohesion and φ is the dynamicfriction angle of rock

According to Formulas (4)ndash(6) under the condition ofthe single hole when the crack is formed by the tangentialtensile stress the radial stress σr should be satisfied

σr ge(1minus μ)Std

μ (7)

At the same time at the crack tip under the blastingstress wave action it is

KdI

πr

radicP2Ylowastmin (8)

where KdI is the dynamic fracture toughness and Ylowastmin is

a dimensionless stress intensity factor at the crack tip whichreflects the size and shape of the crack and it is an inherentindex of the rock material

Under the continuous action of the explosive stress wavethe crack continues to expand and should be satisfied asfollows at the crack tip

KId gtKdI (9)

where KId is the dynamic stress intensity factor at the cracktip which varies with the crack propagation

It can be seen that Formula (7) is the criterion conditionof initial crack formation during slit charge blasting andFormula (9) is the criterion condition of crack propagationand extension under the blasting progress

5 Directional Blasting Experiment UsingSlit Charge

According to the actual engineering geology the blasting testusing the slit charge technology was carried out at the samefree face with the left and right positions separately Amongthem the surrounding hole of the left side uses the ordinarycharge structure and the surrounding hole of the right sideadopts a slit charge structure (erefore it can make a moreaccurate comparison and analysis for the slit charge tech-nique (e blasting effect can be measured by parameterssuch as the over excavation amount and the half hole ratioafter blasting (e specific test is described as follows

51 Production of the Slit Pipe (e slit pipe is made of thePVC tube with an outer diameter of 32mm and an inner

Advances in Civil Engineering 5

diameter of 30mm With an emulsion explosive inside thediameter of the explosive is 32mm and the slit width of theslit pipe is 2mm as shown in Figure 3

It must be noticed that in the process of charging thedirection of the slit must be consistent with the direction ofthe contour of the tunnel cross section Otherwise theexplosive energy will burst more along the other directionsbut induce the tunnel forming worse

It is a key point that must be paid attention before thepreparation of the slit charge and it is also the inherentattribute determined by the directional fracture blastingprinciple of the slit charge

52 Arrangement of the Blasting Hole (e distances of thesurrounding hole both in the left side and the right side were300mm As for the left side the ordinary explosive chargewas installed with three intervals and each length was550mm At the bottom of the hole it was charged with 05volume explosive and the other 025 volumes were installedat each section However the surrounding hole in the rightside was charged using the slit charge with the same installedway and explosive quantity

(e blasting cutting method is straight parallel cuttingway (e layout of the blasting hole before and after drillingis shown in Figure 4

53 Blasting Scheme Based on the above theory of di-rectional fracture technology of slit charge the blasting

scheme is designed(e blasting scheme for the slit charge isshown in Figure 5

(e blasting sequence is divided into 9 segments whichstarts from the cutting hole auxiliary hole to the sur-rounding hole and in the end to the bottom hole

(e length of blockage in the cutting hole is 600mm andthat in the other holes is 300mm

(e number of explosives and detonator segments ineach hole is shown in Table 1 and the section area is1215m2 and the specific charge is 251 kgm3

54 Blasting Effect (e designed footage driving cycle is 2meters while the penetration of blasting has reached 17min the left and 195m in the right which corresponds to theordinary and slit charge separately Meanwhile the utili-zation ratio of blasting hole in the right is higher

(e right side using the slit charge has more than 90 ofthe half hole rate and the blasting effect is smooth and evenHowever the effect of the smooth blasting in the left side isnot so good As can be seen from Figure 6 the rock concaveand convex exist a lot and the half-hole ratio is low

Image process of the profile after blasting and the ratio ofover excavation or under excavation are calculated by theproportional image It is found that over excavation quantityof the right side using the slit charge is small than that in theleft side And it shows a better blasting effect using the slitcharge (ose phenomenon and descriptions illuminate thatthe surrounding holes using the slit charge could make thecross section contour of the tunnel better and smooth afterblasting

Figure 3 Slit pipe

(a) (b)

Figure 4 Borehole distribution

6 Advances in Civil Engineering

Furthermore the variety between the charge composi-tion and the charge structure is the main reason for thedifference of the blasting effect

According to the blasting principle described above itcan be found that as the surrounding hole adopts the slitcharge way it can be easier to achieve directional fracture

123

456

7

89

10

11 1213

14

15

1617

18

19

20

2122

23

24

25

2627

28

29

30

31

3233

34

35

36

37

3839 40

41

42

43

44

45

4647

48

49

50

51

5253

5455

5657 58 59 60 61 62

6364

65

66

67

68

69

70

71

72

8073 74 75 76 77 78 79

298

485 517485

442

435

529

4542150439

442

6154300

1054

200

2000

88deg

35560

425 594 629 173

Figure 5 Blasting scheme of the slit charge technology

Table 1 Blasting parameters table for the scheme

Hole name Hole number Number of holesCharge quantity

Detonator orderEach hole Total weight (kg)

Empty hole 1 1 0 00Cutting hole 2ndash7 6 5 90 1Auxiliary hole 8ndash10 3 5 45 3Auxiliary hole 11ndash12 2 5 30 5Auxiliary hole 13ndash21 9 35 945 7Auxiliary hole 22ndash32 11 25 825 9Auxiliary hole 33ndash46 14 25 105 11Peripheral hole 47ndash72 26 15 90 15Bottom hole 74ndash79 6 3 54 17Bottom hole 7380 2 3 18 19Total 80 609

Advances in Civil Engineering 7

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

mechanism is analyzed either to be tensile failure or to betensile-shear failure Mainly it is a pure compressive stresscarried out on the rock by the shock wave and the stress waveunder blasting Only when the wave propagates to the freesurface the wave reflection occurs and the tensile unloadingwave is produced (erefore the rock is subjected to tensilestress which is beneficial to the rock cracking But thecompression failure is produced on the rock wall very nearthe charge hole and the rock wall is directly damaged intorock powder by the explosion wave

Precisely because of the existence of the slit chargeblasting hole the compression and tensile shock waves alongthe slit direction are more strongly influenced than that inthe other directions Especially the crack surface which hasbeen caused by the early shock wave has been largely im-pacted by the subsequent shock wave causing the rock massin the slit direction to be more easily unloaded spalling andcrushing At the same time explosive gas is more likely toexpand along these cracks and the role of explosive gas inthe slit is more intense than that originated by ordinarycartridge Definitely because of the slit charge the rock masssurrounding the cutting seam is much easier to producetensile fracture and easier to be broken out

Furthermore the role of slit charge for the single blastinghole can be divided into the following aspects Firstly thecutting seam plays a good role in accumulating the explosivewave after blasting Most of the explosive energy is prop-agated along the cutting seam to the rock wall of the blastinghole and the tangential stress produced by the blastingcauses the radial crack around the blasting hole and thecrack is extended forward by the subsequent explosive gasSecondly the slit pipe has a negligible effect on the explosiveenergy Because of the slit pipe explosive energy and det-onating gas are limited to the slit pipe for a certain periodwhich is a little longer than that of the nonslit pipe

(erefore the energy will be released for a longer timeand the residence time of the explosive gas in the charge spaceis prolonged Moreover the slit pipe has a good guiding effecton blasting energyMost of the energy is released along the slitdirection which is more fully blasted and the deformation ismuch more than the direction vertical to the slit or otherdirections Finally the slit charge technology has a certainprotective effect on the blasting hole wall Due to the waveresistance difference between the slit pipe and the rockmedium in addition to the transmission wave of the slit pipethe reflection wave will also occur which could be limited inthe slit pipe and wait for the energy to be released again Andthe released energy is still more transmitted from the slitDuring this process the rock blasting hole which is not alongthe slit direction is protected

As for the blasting engineering the cutting seam packageand the slit charge technology are used in the surroundingblasting hole which can fully play the protective effect on therock wall and also lead to the directional and concentratedeffects

It should be noted that due to the existence of the slithole a free surface is produced in the rock mass and thestress concentration occurs It means that the stress here isfar greater than the stress in other places and the rock

between the slit holes is subjected to not only the impactpressure but also the tensile stress Especially the connecteddirection of the slit hole is the place where the maximumtensile stress is generated and the rock failure caused bytensile stress is more likely to occur In the case of simul-taneous initiation of a double slit charge way the stress waveis firstly propagated along the slit direction resulting in theinitial crack (en with the opposite propagation of thestress waves between the two holes the peak stress of theblasting can reach a number of several GPa in the center Sothe initial crack can propagate through each other undersuch high stress

At the same time from the point of the superposition ofthe stress wave the crack formation should be analyzed It isfound that the penetrating crack can be formed between thetwo holes through the reasonable design of the blasting holediameter the slit pipe diameter the slit charge size and so on

To sum up the slit hole can lead to the rock failure moreeasily along the line between the slit holes and the slit chargeplays a good guidance role in the failure process which ismore conducive to the performance of the explosive

4 Directional Blasting Technology UsingSlit Charge

Definitely the characteristics of the high-level radioactivewaste geological disposal demand a higher safety grade forthe buried nuclear waste Rock permeability increases by theformation of new cracks in the damaged area and the ex-pansion of the original fissure in the rock (erefore thepotential channel for the nuclide migration is provided Inaddition the mechanical properties of the rock and theoperation period of the disposal repository are highlyinfluenced by the excavation damage No matter whichexcavation method is adopted the rock breaking effect andthe disturbance to the surrounding rock are two mainconsiderable factors in the construction and monitoringprogress and these two factors restrict each other

For the geological disposal of high-level radioactivewaste it is very important to recognize the relationshipbetween the elastic modulus deformation permeabilitycoefficient heat conduction coefficient and solute diffusioncoefficient of the excavation zone

At the same time the blasting design and damageverification for rock mass are still a hot topic in blastingengineering Especially for the geological disposal of high-level radioactive waste how to carry out the blasting designof engineering rock mass is a challenge

(e geological disposal facilities of high-level radioactivewaste extend from the surface to a certain depth in the deepunderground which requires that the surrounding rockdamage caused by the excavation is as small as possiblebecause the fracture of the surrounding rock will continue toinitiate expand or even interconnect in the rock massresulting in the loss of the disposed nuclear waste in a certainperiod of time which is absolutely not allowed No matterblasting or mechanical excavation method is used thesurrounding rock will be damaged and this damage isunavoidable

4 Advances in Civil Engineering

(erefore it is very important to adopt a suitable methodto reduce the rock damage(rough the above description itcan be seen that accurate blasting could be achieved by theslit charge directional blasting technology which can playthe role of directional blasting energy gathering blastingand the protection of surrounding rock And it can lead toa small damage range and can ensure the long-term safety ofthe geological disposal of high-level radioactive waste

(e essence of directional fracture blasting of the slitcharge is that the cutting slit with different angles shapesand numbers on the certain density and strength explosiveshell is formed (en the charge mode with a certain ac-cumulation of explosive energy is generated between the slitcharge and the blasting hole (e design blasting parametersand the failure criteria of directional blasting using the slitcharge are discussed below

41 Design of the Blasting Parameters (e hole spacing isquantified by the theoretical calculation and semiempiricalanalysis (e strength coefficient of the rock in the experi-mental tunnel is 8 and the wave velocity is 3500ms (eemulsion explosive is used and the air uncoupled chargeway is adopted Explosive density is 1000 kgm3 and thevelocity of the explosive is 4000ms (e diameter of theexplosive is 32times10minus2m the diameter of the blasting hole is42times10minus2m and the length of the hole is 20m

According to the blasting principle the radial stress andtangential stress of rock mass at a distance r away from thecenter of the borehole are respectively

σr P2Tb

T1113874 1113875

a

σθ bσr

(1)

where σr is the radial stress σθ is the shear stress b is theratio of the tangential stress to the radial stress andb μ(1minus μ) a is the attenuation index of the stress waveand a 2minus b Tb is the radius of the blasting hole T is theradius of the explosive and P2 is the impact stress on theblasting hole wall surface

(e impact pressure on the hole wall as using theuncoupling charge is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6

n (2)

where ρ0 is the explosives densityD is the explosive velocitywhile dc and db are the diameter of the explosive and theblasting hole and n is the pressure increasing coefficient ofthe detonation impacting on the hole wall

However when the air uncoupled charge is adopted theimpact pressure on the hole wall is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6Lc

Lc + La1113888 1113889n (3)

where La is the length of the air column interval and Lc is thelength of the explosive charged

42 Criterion of the Directional Blasting TechnologyUnder the action of tangential tensile stress the criterioncondition of breaking fracture is

σθ ge Std (4)

where Std is the dynamic tensile strength of the rockMoreover the relationship between tangential stress andradial stress is

σθ μσr

(1minus μ) (5)

Std C + σθ tanφ (6)

where C is the dynamic cohesion and φ is the dynamicfriction angle of rock

According to Formulas (4)ndash(6) under the condition ofthe single hole when the crack is formed by the tangentialtensile stress the radial stress σr should be satisfied

σr ge(1minus μ)Std

μ (7)

At the same time at the crack tip under the blastingstress wave action it is

KdI

πr

radicP2Ylowastmin (8)

where KdI is the dynamic fracture toughness and Ylowastmin is

a dimensionless stress intensity factor at the crack tip whichreflects the size and shape of the crack and it is an inherentindex of the rock material

Under the continuous action of the explosive stress wavethe crack continues to expand and should be satisfied asfollows at the crack tip

KId gtKdI (9)

where KId is the dynamic stress intensity factor at the cracktip which varies with the crack propagation

It can be seen that Formula (7) is the criterion conditionof initial crack formation during slit charge blasting andFormula (9) is the criterion condition of crack propagationand extension under the blasting progress

5 Directional Blasting Experiment UsingSlit Charge

According to the actual engineering geology the blasting testusing the slit charge technology was carried out at the samefree face with the left and right positions separately Amongthem the surrounding hole of the left side uses the ordinarycharge structure and the surrounding hole of the right sideadopts a slit charge structure (erefore it can make a moreaccurate comparison and analysis for the slit charge tech-nique (e blasting effect can be measured by parameterssuch as the over excavation amount and the half hole ratioafter blasting (e specific test is described as follows

51 Production of the Slit Pipe (e slit pipe is made of thePVC tube with an outer diameter of 32mm and an inner

Advances in Civil Engineering 5

diameter of 30mm With an emulsion explosive inside thediameter of the explosive is 32mm and the slit width of theslit pipe is 2mm as shown in Figure 3

It must be noticed that in the process of charging thedirection of the slit must be consistent with the direction ofthe contour of the tunnel cross section Otherwise theexplosive energy will burst more along the other directionsbut induce the tunnel forming worse

It is a key point that must be paid attention before thepreparation of the slit charge and it is also the inherentattribute determined by the directional fracture blastingprinciple of the slit charge

52 Arrangement of the Blasting Hole (e distances of thesurrounding hole both in the left side and the right side were300mm As for the left side the ordinary explosive chargewas installed with three intervals and each length was550mm At the bottom of the hole it was charged with 05volume explosive and the other 025 volumes were installedat each section However the surrounding hole in the rightside was charged using the slit charge with the same installedway and explosive quantity

(e blasting cutting method is straight parallel cuttingway (e layout of the blasting hole before and after drillingis shown in Figure 4

53 Blasting Scheme Based on the above theory of di-rectional fracture technology of slit charge the blasting

scheme is designed(e blasting scheme for the slit charge isshown in Figure 5

(e blasting sequence is divided into 9 segments whichstarts from the cutting hole auxiliary hole to the sur-rounding hole and in the end to the bottom hole

(e length of blockage in the cutting hole is 600mm andthat in the other holes is 300mm

(e number of explosives and detonator segments ineach hole is shown in Table 1 and the section area is1215m2 and the specific charge is 251 kgm3

54 Blasting Effect (e designed footage driving cycle is 2meters while the penetration of blasting has reached 17min the left and 195m in the right which corresponds to theordinary and slit charge separately Meanwhile the utili-zation ratio of blasting hole in the right is higher

(e right side using the slit charge has more than 90 ofthe half hole rate and the blasting effect is smooth and evenHowever the effect of the smooth blasting in the left side isnot so good As can be seen from Figure 6 the rock concaveand convex exist a lot and the half-hole ratio is low

Image process of the profile after blasting and the ratio ofover excavation or under excavation are calculated by theproportional image It is found that over excavation quantityof the right side using the slit charge is small than that in theleft side And it shows a better blasting effect using the slitcharge (ose phenomenon and descriptions illuminate thatthe surrounding holes using the slit charge could make thecross section contour of the tunnel better and smooth afterblasting

Figure 3 Slit pipe

(a) (b)

Figure 4 Borehole distribution

6 Advances in Civil Engineering

Furthermore the variety between the charge composi-tion and the charge structure is the main reason for thedifference of the blasting effect

According to the blasting principle described above itcan be found that as the surrounding hole adopts the slitcharge way it can be easier to achieve directional fracture

123

456

7

89

10

11 1213

14

15

1617

18

19

20

2122

23

24

25

2627

28

29

30

31

3233

34

35

36

37

3839 40

41

42

43

44

45

4647

48

49

50

51

5253

5455

5657 58 59 60 61 62

6364

65

66

67

68

69

70

71

72

8073 74 75 76 77 78 79

298

485 517485

442

435

529

4542150439

442

6154300

1054

200

2000

88deg

35560

425 594 629 173

Figure 5 Blasting scheme of the slit charge technology

Table 1 Blasting parameters table for the scheme

Hole name Hole number Number of holesCharge quantity

Detonator orderEach hole Total weight (kg)

Empty hole 1 1 0 00Cutting hole 2ndash7 6 5 90 1Auxiliary hole 8ndash10 3 5 45 3Auxiliary hole 11ndash12 2 5 30 5Auxiliary hole 13ndash21 9 35 945 7Auxiliary hole 22ndash32 11 25 825 9Auxiliary hole 33ndash46 14 25 105 11Peripheral hole 47ndash72 26 15 90 15Bottom hole 74ndash79 6 3 54 17Bottom hole 7380 2 3 18 19Total 80 609

Advances in Civil Engineering 7

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

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(erefore it is very important to adopt a suitable methodto reduce the rock damage(rough the above description itcan be seen that accurate blasting could be achieved by theslit charge directional blasting technology which can playthe role of directional blasting energy gathering blastingand the protection of surrounding rock And it can lead toa small damage range and can ensure the long-term safety ofthe geological disposal of high-level radioactive waste

(e essence of directional fracture blasting of the slitcharge is that the cutting slit with different angles shapesand numbers on the certain density and strength explosiveshell is formed (en the charge mode with a certain ac-cumulation of explosive energy is generated between the slitcharge and the blasting hole (e design blasting parametersand the failure criteria of directional blasting using the slitcharge are discussed below

41 Design of the Blasting Parameters (e hole spacing isquantified by the theoretical calculation and semiempiricalanalysis (e strength coefficient of the rock in the experi-mental tunnel is 8 and the wave velocity is 3500ms (eemulsion explosive is used and the air uncoupled chargeway is adopted Explosive density is 1000 kgm3 and thevelocity of the explosive is 4000ms (e diameter of theexplosive is 32times10minus2m the diameter of the blasting hole is42times10minus2m and the length of the hole is 20m

According to the blasting principle the radial stress andtangential stress of rock mass at a distance r away from thecenter of the borehole are respectively

σr P2Tb

T1113874 1113875

a

σθ bσr

(1)

where σr is the radial stress σθ is the shear stress b is theratio of the tangential stress to the radial stress andb μ(1minus μ) a is the attenuation index of the stress waveand a 2minus b Tb is the radius of the blasting hole T is theradius of the explosive and P2 is the impact stress on theblasting hole wall surface

(e impact pressure on the hole wall as using theuncoupling charge is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6

n (2)

where ρ0 is the explosives densityD is the explosive velocitywhile dc and db are the diameter of the explosive and theblasting hole and n is the pressure increasing coefficient ofthe detonation impacting on the hole wall

However when the air uncoupled charge is adopted theimpact pressure on the hole wall is as follows

P2 18ρ0D

2 dc

db1113888 1113889

6Lc

Lc + La1113888 1113889n (3)

where La is the length of the air column interval and Lc is thelength of the explosive charged

42 Criterion of the Directional Blasting TechnologyUnder the action of tangential tensile stress the criterioncondition of breaking fracture is

σθ ge Std (4)

where Std is the dynamic tensile strength of the rockMoreover the relationship between tangential stress andradial stress is

σθ μσr

(1minus μ) (5)

Std C + σθ tanφ (6)

where C is the dynamic cohesion and φ is the dynamicfriction angle of rock

According to Formulas (4)ndash(6) under the condition ofthe single hole when the crack is formed by the tangentialtensile stress the radial stress σr should be satisfied

σr ge(1minus μ)Std

μ (7)

At the same time at the crack tip under the blastingstress wave action it is

KdI

πr

radicP2Ylowastmin (8)

where KdI is the dynamic fracture toughness and Ylowastmin is

a dimensionless stress intensity factor at the crack tip whichreflects the size and shape of the crack and it is an inherentindex of the rock material

Under the continuous action of the explosive stress wavethe crack continues to expand and should be satisfied asfollows at the crack tip

KId gtKdI (9)

where KId is the dynamic stress intensity factor at the cracktip which varies with the crack propagation

It can be seen that Formula (7) is the criterion conditionof initial crack formation during slit charge blasting andFormula (9) is the criterion condition of crack propagationand extension under the blasting progress

5 Directional Blasting Experiment UsingSlit Charge

According to the actual engineering geology the blasting testusing the slit charge technology was carried out at the samefree face with the left and right positions separately Amongthem the surrounding hole of the left side uses the ordinarycharge structure and the surrounding hole of the right sideadopts a slit charge structure (erefore it can make a moreaccurate comparison and analysis for the slit charge tech-nique (e blasting effect can be measured by parameterssuch as the over excavation amount and the half hole ratioafter blasting (e specific test is described as follows

51 Production of the Slit Pipe (e slit pipe is made of thePVC tube with an outer diameter of 32mm and an inner

Advances in Civil Engineering 5

diameter of 30mm With an emulsion explosive inside thediameter of the explosive is 32mm and the slit width of theslit pipe is 2mm as shown in Figure 3

It must be noticed that in the process of charging thedirection of the slit must be consistent with the direction ofthe contour of the tunnel cross section Otherwise theexplosive energy will burst more along the other directionsbut induce the tunnel forming worse

It is a key point that must be paid attention before thepreparation of the slit charge and it is also the inherentattribute determined by the directional fracture blastingprinciple of the slit charge

52 Arrangement of the Blasting Hole (e distances of thesurrounding hole both in the left side and the right side were300mm As for the left side the ordinary explosive chargewas installed with three intervals and each length was550mm At the bottom of the hole it was charged with 05volume explosive and the other 025 volumes were installedat each section However the surrounding hole in the rightside was charged using the slit charge with the same installedway and explosive quantity

(e blasting cutting method is straight parallel cuttingway (e layout of the blasting hole before and after drillingis shown in Figure 4

53 Blasting Scheme Based on the above theory of di-rectional fracture technology of slit charge the blasting

scheme is designed(e blasting scheme for the slit charge isshown in Figure 5

(e blasting sequence is divided into 9 segments whichstarts from the cutting hole auxiliary hole to the sur-rounding hole and in the end to the bottom hole

(e length of blockage in the cutting hole is 600mm andthat in the other holes is 300mm

(e number of explosives and detonator segments ineach hole is shown in Table 1 and the section area is1215m2 and the specific charge is 251 kgm3

54 Blasting Effect (e designed footage driving cycle is 2meters while the penetration of blasting has reached 17min the left and 195m in the right which corresponds to theordinary and slit charge separately Meanwhile the utili-zation ratio of blasting hole in the right is higher

(e right side using the slit charge has more than 90 ofthe half hole rate and the blasting effect is smooth and evenHowever the effect of the smooth blasting in the left side isnot so good As can be seen from Figure 6 the rock concaveand convex exist a lot and the half-hole ratio is low

Image process of the profile after blasting and the ratio ofover excavation or under excavation are calculated by theproportional image It is found that over excavation quantityof the right side using the slit charge is small than that in theleft side And it shows a better blasting effect using the slitcharge (ose phenomenon and descriptions illuminate thatthe surrounding holes using the slit charge could make thecross section contour of the tunnel better and smooth afterblasting

Figure 3 Slit pipe

(a) (b)

Figure 4 Borehole distribution

6 Advances in Civil Engineering

Furthermore the variety between the charge composi-tion and the charge structure is the main reason for thedifference of the blasting effect

According to the blasting principle described above itcan be found that as the surrounding hole adopts the slitcharge way it can be easier to achieve directional fracture

123

456

7

89

10

11 1213

14

15

1617

18

19

20

2122

23

24

25

2627

28

29

30

31

3233

34

35

36

37

3839 40

41

42

43

44

45

4647

48

49

50

51

5253

5455

5657 58 59 60 61 62

6364

65

66

67

68

69

70

71

72

8073 74 75 76 77 78 79

298

485 517485

442

435

529

4542150439

442

6154300

1054

200

2000

88deg

35560

425 594 629 173

Figure 5 Blasting scheme of the slit charge technology

Table 1 Blasting parameters table for the scheme

Hole name Hole number Number of holesCharge quantity

Detonator orderEach hole Total weight (kg)

Empty hole 1 1 0 00Cutting hole 2ndash7 6 5 90 1Auxiliary hole 8ndash10 3 5 45 3Auxiliary hole 11ndash12 2 5 30 5Auxiliary hole 13ndash21 9 35 945 7Auxiliary hole 22ndash32 11 25 825 9Auxiliary hole 33ndash46 14 25 105 11Peripheral hole 47ndash72 26 15 90 15Bottom hole 74ndash79 6 3 54 17Bottom hole 7380 2 3 18 19Total 80 609

Advances in Civil Engineering 7

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

diameter of 30mm With an emulsion explosive inside thediameter of the explosive is 32mm and the slit width of theslit pipe is 2mm as shown in Figure 3

It must be noticed that in the process of charging thedirection of the slit must be consistent with the direction ofthe contour of the tunnel cross section Otherwise theexplosive energy will burst more along the other directionsbut induce the tunnel forming worse

It is a key point that must be paid attention before thepreparation of the slit charge and it is also the inherentattribute determined by the directional fracture blastingprinciple of the slit charge

52 Arrangement of the Blasting Hole (e distances of thesurrounding hole both in the left side and the right side were300mm As for the left side the ordinary explosive chargewas installed with three intervals and each length was550mm At the bottom of the hole it was charged with 05volume explosive and the other 025 volumes were installedat each section However the surrounding hole in the rightside was charged using the slit charge with the same installedway and explosive quantity

(e blasting cutting method is straight parallel cuttingway (e layout of the blasting hole before and after drillingis shown in Figure 4

53 Blasting Scheme Based on the above theory of di-rectional fracture technology of slit charge the blasting

scheme is designed(e blasting scheme for the slit charge isshown in Figure 5

(e blasting sequence is divided into 9 segments whichstarts from the cutting hole auxiliary hole to the sur-rounding hole and in the end to the bottom hole

(e length of blockage in the cutting hole is 600mm andthat in the other holes is 300mm

(e number of explosives and detonator segments ineach hole is shown in Table 1 and the section area is1215m2 and the specific charge is 251 kgm3

54 Blasting Effect (e designed footage driving cycle is 2meters while the penetration of blasting has reached 17min the left and 195m in the right which corresponds to theordinary and slit charge separately Meanwhile the utili-zation ratio of blasting hole in the right is higher

(e right side using the slit charge has more than 90 ofthe half hole rate and the blasting effect is smooth and evenHowever the effect of the smooth blasting in the left side isnot so good As can be seen from Figure 6 the rock concaveand convex exist a lot and the half-hole ratio is low

Image process of the profile after blasting and the ratio ofover excavation or under excavation are calculated by theproportional image It is found that over excavation quantityof the right side using the slit charge is small than that in theleft side And it shows a better blasting effect using the slitcharge (ose phenomenon and descriptions illuminate thatthe surrounding holes using the slit charge could make thecross section contour of the tunnel better and smooth afterblasting

Figure 3 Slit pipe

(a) (b)

Figure 4 Borehole distribution

6 Advances in Civil Engineering

Furthermore the variety between the charge composi-tion and the charge structure is the main reason for thedifference of the blasting effect

According to the blasting principle described above itcan be found that as the surrounding hole adopts the slitcharge way it can be easier to achieve directional fracture

123

456

7

89

10

11 1213

14

15

1617

18

19

20

2122

23

24

25

2627

28

29

30

31

3233

34

35

36

37

3839 40

41

42

43

44

45

4647

48

49

50

51

5253

5455

5657 58 59 60 61 62

6364

65

66

67

68

69

70

71

72

8073 74 75 76 77 78 79

298

485 517485

442

435

529

4542150439

442

6154300

1054

200

2000

88deg

35560

425 594 629 173

Figure 5 Blasting scheme of the slit charge technology

Table 1 Blasting parameters table for the scheme

Hole name Hole number Number of holesCharge quantity

Detonator orderEach hole Total weight (kg)

Empty hole 1 1 0 00Cutting hole 2ndash7 6 5 90 1Auxiliary hole 8ndash10 3 5 45 3Auxiliary hole 11ndash12 2 5 30 5Auxiliary hole 13ndash21 9 35 945 7Auxiliary hole 22ndash32 11 25 825 9Auxiliary hole 33ndash46 14 25 105 11Peripheral hole 47ndash72 26 15 90 15Bottom hole 74ndash79 6 3 54 17Bottom hole 7380 2 3 18 19Total 80 609

Advances in Civil Engineering 7

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

Furthermore the variety between the charge composi-tion and the charge structure is the main reason for thedifference of the blasting effect

According to the blasting principle described above itcan be found that as the surrounding hole adopts the slitcharge way it can be easier to achieve directional fracture

123

456

7

89

10

11 1213

14

15

1617

18

19

20

2122

23

24

25

2627

28

29

30

31

3233

34

35

36

37

3839 40

41

42

43

44

45

4647

48

49

50

51

5253

5455

5657 58 59 60 61 62

6364

65

66

67

68

69

70

71

72

8073 74 75 76 77 78 79

298

485 517485

442

435

529

4542150439

442

6154300

1054

200

2000

88deg

35560

425 594 629 173

Figure 5 Blasting scheme of the slit charge technology

Table 1 Blasting parameters table for the scheme

Hole name Hole number Number of holesCharge quantity

Detonator orderEach hole Total weight (kg)

Empty hole 1 1 0 00Cutting hole 2ndash7 6 5 90 1Auxiliary hole 8ndash10 3 5 45 3Auxiliary hole 11ndash12 2 5 30 5Auxiliary hole 13ndash21 9 35 945 7Auxiliary hole 22ndash32 11 25 825 9Auxiliary hole 33ndash46 14 25 105 11Peripheral hole 47ndash72 26 15 90 15Bottom hole 74ndash79 6 3 54 17Bottom hole 7380 2 3 18 19Total 80 609

Advances in Civil Engineering 7

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

Rock around the surrounding hole is destroyed strictly alongthe cutting direction under blasting

(e explosive gas is triggered through the crack causedby the shock wave (just started in dozens of microseconds)and wedged into the internal microcracks in the sur-rounding rock (e energy accumulated in the crack tipmore and more and the stress concentration is more ob-vious which leads to a greater dynamic stress intensityfactor It is much easier to extend and expand along thedirection of the initial crack which is more beneficial to theeffect of the subsequent explosion stress wave and it hasplayed a good guidance role

Correspondingly there is less phenomenon of overexcavation around the tunnel and the smooth blasting effectis improved It can be seen that the reasonable directionalfracture technology using the slit charge is very important tosmooth blasting

6 Conclusions

(1) Based on the directional blasting technology of theslit charge the explosive process and the failureprinciple are thoroughly explored Combined withthe blasting engineering for high-level radioactivewaste geological disposal the parameters of di-rectional blasting in the BET exploration facility hasbeen designed and discussed

(2) (e initiation and failure criteria of directionalfracture blasting are analyzed deeply (e dynamiccompressive strength dynamic tensile strengthdynamic elasticity modulus dynamic Poissonrsquos ratiodynamic fracture toughness and dynamic stressintensity factor and other parameters are used todescribe the criterion

(3) Moreover the blasting experiment of slit charge atdifferent positions but the same tunnel face wascarried out It is found that the blasting effect is goodat the right side using the slit charge which provedthat the blasting parameters calculated are reason-able It is suitable to apply the directional fractureblasting technology using the slit charge to the high-level radioactive waste geological disposal

It should be pointed out that the drilling and blastingmethod covers many kinds of blasting parameters (e dataobtained are only the preliminary exploration of the

directional fracture blasting technology in the geologicaldisposal of high-level radioactive waste It can provide theexperimental data and theoretical support for the blastingexcavation of the high-level radioactive waste geologicaldisposal and it also has a certain guiding significance for theblasting excavation of the deep underground engineering

Data Availability

(e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

(e authors declare that there are no conflicts of interestassociated with this publication

Acknowledgments

(is work was supported by the National Natural ScienceFoundation of China (grant no 41202207) (e authors aremost grateful to Professor Yue Z W for the valuable helpwith the tests

References

[1] National Development and Reform Commission Mediumand Long-Term Plan for National Nuclear Power Development2005-2020 National Development and Reform CommissionBeijing China 2007

[2] Ministry of environmental protection of the Peoplersquos Republicof China Regulations on Radioactive Waste Management(GB14500-93) State Technical Supervision Bureau BeijingChina 1993

[3] National Nuclear Safety Agency Siting of Radioactive WasteGeological Disposal (HAD40106) National Nuclear SafetyAgency Beijing China 1998

[4] Peoplersquos Republic of China Law of Prevention and Control ofRadioactive Pollution Law Press Beijing China 2003

[5] National Defense Science Technology and Industry Com-mission Ministry of Science and Technology and State En-vironmental Protection Administration Guidelines forResearch and Development Planning of Geological Disposal ofHigh-level Radioactive Wastes National Defense ScienceTechnology and Industry Commission Beijing China 2006

[6] Z Pan and Q Q Hu Strategic Study on Geological Disposal ofHigh-Level Radioactive Waste Atomic Energy Press BeijingChina 2009

[7] Q Q Hu ldquoNew progress in rock engineering technology inChinardquo Chinese Engineering Science vol 12 no 8 pp 37ndash482010

[8] J Wang ldquoOn geological disposal of high level radioactivewaste in Chinardquo Geology vol 7 pp 33ndash35 1998

[9] Y Yang Technology and Safety of Blasting in Mine BeijingChina Coal Industry Publishing House Peking China 1991

[10] W Wang Drilling and Blasting BeijingChina Coal IndustryPublishing House Peking China 1984

[11] Y Gu X Li Y Du et al ldquoReasonable smooth blasting factorused in tunnelrdquo Journal of Chongqing University NaturalScience vol 28 no 3 pp 95ndash97 2005

[12] J Dai and Y Yang ldquoAnalysis of controlled perimeter blastingin damaged rockrdquo Journal of University of Mining andTechnology vol 29 no 5 pp 496ndash499 2000

Convex

Concave

Figure 6 Blasting effect

8 Advances in Civil Engineering

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

[13] Y Fu X Li and L Dong ldquoAnalysis of smooth blasting pa-rameters for tunnels in deep damaged rock massrdquo Rock andSoil Mechanics vol 31 no 5 pp 1420ndash1426 2010

[14] L Huang ldquoOptimization and check of the main parameters insmooth blastingrdquo Blasting vol 19 no 3 pp 20-21 2002

[15] J Chen X Li and J Zhang ldquoStudy on blasting parameters ofprotective layer excavation of rock bench based on blastinginduced damagerdquo Chinese Journal of Rock Mechanics andEngineering vol 35 no 1 pp 98ndash108 2016

[16] F Dai K Xia and L Tang ldquoRate dependence of the flexuraltensile strength of Laurentian graniterdquo International Journalof Rock Mechanics and Mining Sciences vol 47 no 3pp 469-475 2009 In press

[17] Q Ma ldquoDefinition of hole-space and burden in smoothblastingrdquo Chinese Journal of Rock Mechanics and Engineeringvol 16 no 6 pp 590ndash594 1997

[18] H Hu ldquo(e selection of smooth blasting parameters andquality control of tunnel in rocksrdquo China Mining Magazinevol 16 no 6 pp 63ndash65 2007

[19] X Wang R Shan and B Huang ldquoApplication research onsmooth blasting for cracked soft rock tunnellingrdquo Blastingvol 25 no 3 pp 12ndash16 2008

[20] D S Chang Y Li and C Wu ldquoExploration and practice ofoptimizing blasting parameters for improving driving effi-ciency of rock roadwaysrdquo Coal Technology vol 26 no 2pp 135ndash137 2007

[21] Y Lu and D Zhang ldquoDiscussion on the parameters of sur-rounding eyes in smooth blasting constructionrdquo Coal MineBlasting vol 3 no 1 pp 7ndash9 2002

[22] Y Guo and D L Zhang ldquoCalculation and analysis of smoothblasting parameters for roadway tunneling in soft rockrdquoMinePressure and Shift Management vol 5 no 1 pp 102ndash1052003

[23] Y Yang R Yang Q G Chen et al ldquoDirectional fracturecontrolled blasting mechanism and production testrdquo Blastingvol 6 pp 40ndash43 1995

[24] R Yang Q Tong and G Yang ldquoExperimental study on cutblasting with slotted cartridgerdquo Coal safety vol 1 pp 11ndash142010

[25] Y Tian H Tian and R Yang ldquoStudy of the cut blasting withslotted cartridge on the rock tunnelrdquo Mine ConstructionTechnology vol 3 no 6 pp 10ndash12 1997

[26] Z Yue G Yang and P Xu ldquoAnalysis of empty hole effect indirectional fracture controlled blastingrdquo Explosion and ShockWaves vol 35 no 3 pp 304ndash311 2015

[27] R Yang X Gao J Zuo et al ldquoExperimental study of blastingwave propagation mechanism on cutting seam cartridgerdquoJournal of Coal Industry vol 35 no 8 pp 1434ndash1440 2014

[28] R Yang C Ding L Yang and Y Wang ldquoExperimental studyon controlled directional blasting on PMMA mediums withflawsrdquo Chinese Journal of Rock Mechanics and Engineeringvol 36 no 3 pp 690ndash696 2017

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom